Disorder-induced topological phase transitions on Lieb lattices

TL;DR

This paper investigates how Anderson disorder can induce topological phase transitions in Lieb lattices with spin-orbit coupling, revealing new disorder-driven topological phases including QSHI and QAHI, even without time-reversal symmetry.

Contribution

It demonstrates that disorder can induce topological phases in Lieb lattices, including QSHI and QAHI, expanding understanding of disorder effects in topological materials.

Findings

Disorder induces QSHI and QAHI phases in Lieb lattices.

Disorder can cause direct NI to QSHI transition in time-reversal invariant systems.

Disorder induces QAHI-QSHI and NI-QAHI-QSHI transitions in time-reversal broken systems.

Abstract

Motivated by the very recent experimental realization of electronic Lieb lattices and research interest on topological states of matter, we study the topological phase transitions driven by Anderson disorder on spin-orbit coupled Lieb lattices in the presence of spin-independent and dependent potentials. By combining the numerical transport and self-consistent Born approximation methods, we found that both time-reversal invariant and broken Lieb lattices can host disorder-induced gapful topological phases, including the quantum spin Hall insulator (QSHI) and quantum anomalous Hall insulator (QAHI) phases. For the time-reversal invariant case, this disorder can induce a topological phase transition directly from normal insulator (NI) to the QSHI. While for the time-reversal broken case, the disorder can induce either a QAHI-QSHI phase transition or a NI-QAHI-QSHI phase transition. Remarkably, the time-reversal broken QSHI phase can be induced by Anderson disorder on the spin-orbit coupled Lieb lattices without time-reversal symmetry.